RFR(xs): 8165936: Potential Heap buffer overflow when seaching timezone info files

[Roger Riggs]

Hi Thomas,

One minor point, it seems a bit asymmetric (@line 150) to cast to 
dirent64 but use dirent in the offsetof calculation.
Otherwise, looks fine.

Roger



On 9/13/2016 8:35 AM, Langer, Christoph wrote:
> Hi Thomas,
>
> your change looks good. I'm also forwarding this to i18n-dev as issues in TimeZone implementation are mostly handled there.
>
> One remark: Can you take the opportunity to also remove the blank between the cast and malloc in line 150: "(struct dirent64 *) malloc..."?
>
> Unfortunately I'm no reviewer, so you still need an official review.
>
> Best regards
> Christoph
>
>> -----Original Message-----
>> From: core-libs-dev [mailto:core-libs-dev-bounces at openjdk.java.net] On Behalf
>> Of Thomas Stüfe
>> Sent: Dienstag, 13. September 2016 12:54
>> To: Java Core Libs <core-libs-dev at openjdk.java.net>
>> Subject: RFR(xs): 8165936: Potential Heap buffer overflow when seaching
>> timezone info files
>>
>> Dear all,
>>
>> please take a look at this small change:
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8165936
>> Webrev:
>> http://cr.openjdk.java.net/~stuefe/webrevs/8165936-Potential-Heap-buffer-
>> overflow-when-seaching-timezone-info-files/webrev.00/webrev/
>>
>> readdir_r is used to iterate over the content of a system directory, but
>> the buffer passed to it is too small: Its size should include the size of
>> the dirent structure itself (minus the d_name member).
>>
>> The fix also now checks the return code of pathconf(), and if pathconf()
>> returns an error, falls back to the NAME_MAX compile time constant.
>> Finally, it imposes a minimum size for the buffer, because on older System
>> V systems NAME_MAX may be surprisingly small and readdir_r will not check
>> the output buffer size. I think it is better to err on the safe side here.
>>
>> Kind Regards, Thomas